---
title: Introduction to Apollo Server
subtitle: Learn how to build scalable, production-ready GraphQL APIs
description: Learn how Apollo Server simplifies building GraphQL APIs with its straightforward setup and support for any data source or client.
---

> 📣 **Apollo Server 5 is generally available!**
>
> Apollo Server 5 is a small upgrade focused largely on adjusting which dependency versions are supported. [Upgrading from v4 to v5](/apollo-server/migration/) usually only takes a few minutes. Because the behavior of Apollo Server has changed minimally between v4 and v5, these docs document both versions.
>
> Still on Apollo Server 3? AS3 has been end-of-life since October 2024. We've got a [full migration guide for upgrading directly from v3 to v5](/apollo-server/migration-from-v3/). Docs for v3 are [available here](/apollo-server/v3/).

**Apollo Server is an [open-source](https://github.com/apollographql/apollo-server), spec-compliant GraphQL server** that's compatible with any GraphQL client, including [Apollo Client](/react). It's the best way to build a production-ready, self-documenting GraphQL API that can use data from any source.

<img src="./images/introduction.jpg" width="600" alt="Diagram showing Apollo Server bridging GraphQL Operations to web apps and frameworks" />

#### You can use Apollo Server as:

* The GraphQL server for a [subgraph](/apollo-server/using-federation/apollo-subgraph-setup) in a federated supergraph
* An add-on to any new or existing Node.js apps—this includes apps running on [Express](/apollo-server/api/express-middleware) (including [MERN stack](/apollo-server/integrations/mern) apps), [AWS Lambda](https://www.npmjs.com/package/@as-integrations/aws-lambda), [Azure Functions](https://www.npmjs.com/package/@as-integrations/azure-functions), [Cloudflare](https://www.npmjs.com/package/@as-integrations/cloudflare-workers), [Fastify](https://www.npmjs.com/package/@as-integrations/fastify), and [more](/apollo-server/integrations/integration-index)

#### Apollo Server provides:

*  **Straightforward setup**, so your client developers can start fetching data quickly
*  **Incremental adoption**, enabling you to add features as they're needed
*  **Universal compatibility** with any data source, any build tool, and any GraphQL client
*  **Production readiness**, enabling you to confidently run your graph in production

#### Ready to try it out?

<ButtonLink href="/apollo-server/getting-started" size="lg">
  Get started!
</ButtonLink>
